1. Field of the Invention
A positioning device to facilitate the maintenance of a patent airway by correctly positioning the patient's head under anesthesia during an operation or procedure.
2. Description of the Prior Art
Monitored Anesthesia Care (MAC) anesthesia is commonly used as an anesthetic technique. During MAC, sedative, hypnotic and/or anesthetic drugs introduced into the bloodstream are used in combination with a local anesthetic applied to the operative site. MAC anesthesia may be employed in combination with anesthesia such as spinals, epidurals, and peripheral nerve blocks, which also provide temporary loss of feeling and movement at the operative site. An upper airway obstruction may occur when using MAC anesthesia technique because of respiratory depression and/or relaxation of airway musculature caused by the drugs. For example, a fully-relaxed patient's jaw and tongue may slip back and obstruct the airway.
To reduce the risk of an upper airway obstruction, an anesthetist should position the airway to maintain airway patency. In particular, the anesthetist will manually lift the chin upwards and tilt the head. This correctly positions the head with anterior displacement of the mandible with airway structures; this contributes to allowing air to pass from the pharynx into the trachea and allow patient air exchange. Alternatively a jaw-thrust maneuver may be employed by placing hands at both sides of the mandible and thrusting the jaw forward. Either method requires the anesthetist to support the patient's head manually throughout the surgery.
U.S. Pat. No. 1,131,802 shows a device comprising a frame having a pair of angular adjustable side extensions, a vertically adjustable head rest detachably mounted on the frame with freedom for horizontal adjustment longitudinally of the side extensions, and a pair of vertically adjustable jaw rests mounted on the side extensions for movement toward and away from the head rest.
U.S. Pat. No. 1,441,817 relates to an apparatus comprising a base plate and a pair of spaced jaw props adjustable on the base plate at an angle thereto. The jaw props include the sole projections on the base plate, and the base plate being sufficiently narrow so that it may be placed beneath the neck of a corpse and be adjusted longitudinally of the neck of a corpse while the shoulders of the corpse and the head of the corpse rest upon a head board independently of the base plate.
U.S. Pat. No. 1,729,525 teaches a device comprising a vertically adjustable head rest, jaw rests, angularly and lengthwise adjustable supporting means for the jaw rests carried by the head rest, a supporting structure and head rest having a latch to hold the head rest in adjusted position, including a pair of supports hinged to the head rest and a combined coupling and adjusting device for the supports, the jaw rests being vertically and angularly adjustable with respect to supports, the supports further having the forward ends thereof apertured for receiving the jaw rests and carrying at their forward ends clamping devices for maintaining the jaw rests in adjusted position.
U.S. Pat. No. 1,776,167 shows a device comprising an adjustable head rest element including a pair of oppositely disposed downwardly inclined extensions and a vertical post, an adjustable supporting element including an angle shaped pivoted arm arranged below the head rest element, the supporting element including means for latching the arm, an adjustable coupling device between the post and the arm, a pair of angle shaped oppositely extending jaw rest elements, adjustable coupling devices between the jaw rest elements and the extensions and adjustable shoulder drawing down means pivotally and adjustably connected to the extensions.
U.S. Pat. No. 2,452,816 discloses a jaw supporting device comprising a base member, means for securing the base member to and transversely of a table top, abutments upstanding in adjustable spaced opposition from the base member, and means for selectively adjusting the abutments longitudinally of the base member. Also disclosed are a straight cylindrical stem clampably swiveled to extend upwardly from each abutment's upper end, a tubular element telescoped over each stem and slidable axially thereon, means for clamping the tubular element to and in selectively adjusted positions along the stem, a mounting block clampably swiveled to the free end of each tubular element and a jaw engaging cushion removably and replaceable clipped to and in supported relation against each block.
U.S. Pat. No. 4,700,691 relates to a restraining and supporting device for the head of a patient comprising a head immobilizing contraption connected to the operating table, arm and hand supports for the surgeon, wherein the hand supports are fixed to the head immobilizing contraption through flexible arms, also provided with elements releasing or tightening the flexible arms, which elements are fitted to one of the fingers of the surgeon's hand, or interconnected with hand and/or foot switch. The head immobilizing contraption consists of nape support provided with a three-point bearing for the head and can be set at an adjustable height. A front support clamps down the head into the nape support and is connected to the nape support through a hinged mechanism. The flexible arms are attached to the front support of the head immobilizing contraption.
U.S. Pat. No. 5,524,639 discloses an apparatus intended to maintain or improve a supine patient's airway in a hands-free environment. A frame and detachable pillow device are placed under the patient's head. Mechanisms extend laterally from the frame and provide jaw support members that may be brought under the angles of the jaw. The jaw support members may slide towards and away from the frame, but this sliding movement is regulated by a unidirectional clutch, such as a ratchet and pawl system, which restricts the jaw support members to sliding movement away from the frame only. When the jaw support members are slid away from the frame, they engage the angles of the jaw, and then thrust the jaw forward to maintain or improve the patient's airway. Once the desired anteriorly thrust position of the jaw is achieved, the unidirectional clutch holds the jaw in place until the clutch is released. The weight of the jaw then causes the jaw support members to slide back towards the frame, restoring the jaw to its normal position.